Detect short or long mouse event in BGE
Good question! I was sure this is possible with logic bricks only. Check out the *.blend with a minimal example:



There are two actions:


AC_1: Turn cube by 1 Degree
AC_2: Turn cube by 20 Degree


The cube has a property "prop" initialized by 5, which decreased on every positive pulse when the left mouse button is pressed. 

The releasing event for the left mouse button is detected by the M_RELEASE sensor and is connected to three controllers doing the following:


Executing AC_1 in case the property was larger than zero
Executing AC_2 in case the property was smaller than zero
Resetting the property back to 5 


There should be a lean solution using Python as well. Maybe someone else has this at hand as a Plan B. 

Have fun!